Currently, mobile communication techniques have been widely used in various fields as well as in people's life. Mobile communication system is a communication system in which lots of information transmissions can be established between mobile objects, and between mobile objects and stationary users. The devices on network terminal of a mobile communication system mainly include a base station, a base station controller and core network equipments. The base station mainly consists of a transmission unit, a common control unit, a clock unit, a RF (Radio Frequency) transceiver unit and a base band processing unit. There are no strict standards for interface between the RF transceiver unit and the base band processing unit, and generally, an internal interface is adopted.
In a base station communication system, uplink direction refers to the flow direction of signals transmitted from a mobile telephone and received by the base station, and downlink direction is from the base station to the mobile telephone. In the uplink direction, the received RF signals are performed down conversion and analogue-to-digital conversion by the RF transceiver unit, then are converted into digital signals, and are transmitted to the base band processing unit for operations like demodulating, de-interleaving and channel decoding. In the downlink direction, after being channel coded, interleaved and modulated in the base band processing unit, the digital signals are transmitted to the RF transceiver unit to be performed digital-to-analogue conversion and up conversion. There are digital signal interfaces in both uplink and downlink directions between the RF transceiver unit and the base band processing unit.
The RE transceiver unit and base band processing unit of the base station generally consist of several modules, and usually several base band processing modules are needed to jointly complete the base band processing of one or more RF transceiver modules. In fact, each base band processing module completes the base band processing of several carrier frequencies. Therefore, in uplink direction, it is necessary to transmit signals outputted by one or more RF transceiver modules (TRX) to several base band processing modules (BBP), while in downlink direction, signals outputted by each base band processing module (BBP) are transmitted to the corresponding RF transceiver module (TRX).
The existing method for base band processing module N+M backup is shown as FIG. 1, wherein each base band processing module (BBP) 111 and each RF transceiver module 121 are connected in a meshwork. The features of this method are: 1. in uplink direction, digital signals outputted by each RF transceiver module (TRX) 121 need to be transmitted to all the base band processing modules (BBP) 111; 2. in downlink direction, digital signals outputted by each base band processing module 111 need to be transmitted to all the RF transceiver modules 121; and 3. each BBP 111 or TRX 121 selects signals needing to be processed according to configuration.
This method also has the following disadvantages:
1. the method becomes impracticable when there are a large number of BBP and TRX modules;
2. there are lots of wirings in backplane;
3. the interfaces in BBP and TRX modules are complex;
4. when the BBP and TRX need to be in two or more plugged boxes, there will be a large amount of cables between the plugged boxes, resulting in a poor reliability; and
5. when N>5, the cost will be high.